How does the ultrasonic assist CO₂ immiscible flooding?

Area of Science:

• Petroleum Engineering
• Enhanced Oil Recovery (EOR)
• Carbon Capture, Utilization, and Storage (CCUS)

Background:

• Carbon dioxide (CO2) flooding is crucial for emission reduction and oil production.
• CO2 immiscible flooding faces challenges with low recovery rates and economic viability.
• Need for advanced EOR techniques to overcome limitations of conventional CO2 flooding.

Purpose of the Study:

• To investigate ultrasonic-assisted CO2 immiscible flooding for enhanced oil recovery.
• To analyze the mechanisms behind improved oil recovery using ultrasound.
• To evaluate the impact of ultrasound on residual oil distribution and characteristics.

Main Methods:

• Characterization of residual oil using High Pressure Mercury Injection (HPMI), Nuclear Magnetic Resonance (NMR), and Microscopic Visualization Displacement (MVD).
• Application of ultrasonic-assisted CO2 immiscible flooding (28 KHz, 200 W).
• Analysis of oil recovery rates, residual oil droplet size, and Interfacial Tension (IFT) changes.

Main Results:

• Ultrasonic assistance increased oil recovery from 53.33% to 62.84%.
• Reduced maximum residual oil droplet radius from 81.8 μm to 36.5 μm.
• Ultrasound improved recovery of flake residual oil and slightly improved film residual oil recovery.

Conclusions:

• Ultrasonic-assisted CO2 immiscible flooding enhances EOR by increasing pore/throat radius and reducing CO2-oil IFT.
• High-frequency vibrations from ultrasound reduce oil film thickness, aiding displacement.
• This technique shows promise for scientific research and practical application in the oil industry.